Double lift dobby

ABSTRACT

A double lift dobby for dobby looms, jacquard looms and the like comprising a first and second double arm crank, each of which is rotatably journaled about independent axes spaced from and parallel to each other. One arm of each of the cranks is provided with latch means for selectively engaging a corresponding one of a driven pair of lifting knives. The cranks are thereby rotatable about their axes by and conjointly with the lifting knife after such engagement. The other arms of each of the cranks is interconnected with the means for raising and lowering the heald frame which comprises a lever connected at one end to the first of the cranks and at the other end to the means for lowering the heald frame and a tie rod connected at one end of the second of the cranks and at its other end between the ends of the lever.

Pavlica 4] DOUBLE LIFT DOBBY [75] Inventor: Zdenek Pavlica, Jicin,

Czechoslovakia [73] Assignee: ELITEX Zavody textilniho strojirenstvi,generalni reditelstvi, Liberec, Czechoslovakia [22] Filed: Dec. 29, 1972[21] Appl. No.: 319,308

[30] Foreign Application Priority Data Jan. 4, 1972 Czechoslovakia3672-72 [52] US. Cl. 139/71 [51] Int. Cl. 0031': 1/06 [58] Field ofSearch 139/66 R, 66 A, 68, 71, 139/74, 331

[56] References Cited UNITED STATES PATENTS 3,703,195 11 1972 Schwarz m139/71 FOREIGN PATENTS OR APPLICATIONS 959,899 3/1957 Germany 139/71145] Sept. 3, 19 74 853,856 11/1960 Great Britain 139/71 657,412 9/1951Great Britain 1,106,704

Primary Examiner-James Kee, Chi

Attorney, Agent, or Firm-Murray Schaffer [57] ABSTRACT v g A double liftdobby for dobby looms, jacquard looms and the like comprising a'firstand second double arm crank, each of which is rotatably journaled aboutindependent axes spaced from and parallel to each other. One arm of eachof the cranks is provided with latch means for selectively engaging acorresponding one of a driven pair of lifting knives. The cranks arethereby rotatable about their axes by and conjointly with the liftingknife after such engagement. The other arms of each of the cranks isinterconnected with the means for raising and lowering the heald' framewhich comprises a lever connected at one end to the first of the cranksand at the other end to the means for lowering the heald frame and atierod connected atone end of the second ofthe cranks and at itsother'end between the ends of the lever. 1 I

3 Claims, 1 Drawing Figure 5/1961 Germany 139/71 DOUBLE LIFI DOBBYBACKGROUND OF THE INVENTION The present invention relates to a doublelift dobby loom, jacquard loom and the like and particularly to anarrangement for linking double lift mechanism of the dobby to anassociated heald frame.

In conventional looms the shedding operation is performed by thecooperative manipulation of the several harness heald frames and theassociated hook cords. Conventionally this is accomplished by anarcuately moving lifting knife adapted to engage the hook cords and by alink connected to the heald frame which includes crank means selectivelyengageable with the lifting knife to transmit the motion of the drivenlifting knives to the heald frame. In double lift dobby looms andsimilar jacquard looms a pair of lifting knives are arranged inassociationwith each other and require a pair of corresponding liftingcranks which are interconnected with the means for raising and loweringthe heald frame. The interconnection between the two crank levers hasgenerally employed a balancing or levelling lever by which the motion ofeither or both of the lifting cranks is transmitted to the heald frame.Such interconnections have had the disadvantage in that the motion ofthe balancing lever is derived from its center which has half or less ofthe lift of the lifting cranks. Thus the extent of movement of thebalance lever is small and must be-multiplied several times in order tosufficiently actuate the heald frame.-

It is the object of the present invention to provide an arrangementwhich overcomes the disadvantages of the prior art and provides a dobbywhich maintains its ability of double lifting but which does not requirea complex mechanism for multiplying and transmitting the motion of thelifting cranks to the heald frame.

In particular, the present invention is directed to an improvement forthe form of a dobby mechanism described in our copending applicationfiled on even date herewith corresponding to Czechoslovak patent application No. PV 33-72, dated Jan. 4, 1972, to which reference is made hereas if more fully set forth.

These objects, other objects and numerous advantages will be seen fromthe following disclosure of the preferred embodiments of the presentinvention.

SUMMARY OF INVENTION According to the present invention a double liftdobby for dobby looms, jacquard looms and the like is provided,comprising a first and second double arm crank each of which isrotatably journaled about independent axes spaced from and parallel toeach other. One arm of each-of the cranks is provided with latch meansfor selectively engaging a corresponding one of a driven pair of liftingknives. The cranks are thereby rotatable about their axes by andconjointly with the lifting knife after such engagement. The other armof each of the cranks is interconnected with the means for raising andlowering the heald frame which comprises a lever connected at one end'to the first of the cranks and at the other end to the means forlowering the heald frame and a tie rod connected at one end of thesecond of the cranks and at its other end between the ends of the lever.According to this structurean articulated linkage is provided whereinthe means for raising and lowering the heald frame is actuable uponrotation of the distance between the point of connection of the tie rodtothe lever and the point of connection of the lever withthe means forraising and lowering the heald frame to the entire length between theconnecting ends of the lever itself. This ratio thus insures the propertransmission of the movement of thecranks. I

Still further, in accordance with the present invention, the tie rod isprovided so that it may be adjustably positioned at each of its ends tothe second crank and-- /or to the lever respectively.

Full details of the present invention are given in the followingdescription of the preferred embodiment and will be seen in the attacheddrawing-thereof.

BRIEF DESCRIP'HONOF THE DRAWING I In the drawing:

The FIGURE is a side view of that portion of a high speed dobbymechanism employing-the present invention.

DESCRIPTION OF THE INVENTION The following description and the attacheddrawing provide the structure and operation of a single double liftunit, similar to the type described'in the aforementioned copendingapplication, to which reference might ber of healds in the harness.Consequently, while only one such unit is shown here, it will beappreciated that a conventional loom will. contain several of them,mutually identical. 7

As seen in the figure, the dobby mechanism comprises a pair of fixedaxle shafts la and lb on which are rotatably joumaled double arm cranklevers 2 and 3 respectively carrying at their upper ends pivot pins 4aor 4b about which a latching rocker 5a or 5b is secured.

The shaft axles la and lb each journal, in addition, a carriertnot seen)on the outer end of whichthere is respectively mounted a lifting knife6a or 6b. Each of the carriers is provided with means such'as that shownin the aforementioned copending application by which the lifting knivesmay be given a reciprocatory or oscillatory swinging motion in anarcuate path about a center, which is identical with the center of theshaft axles la and 1b. This center is also identical with the center ofarcuate movement of the latches 5a and 5b, as will be obvious from theconstruction. The rocker latches mounted are provided with their ownstop means which are adapted to engage and abut a portion of the liftingknife, the lifting knife itself being arranged at a height permittingthe inner hook at the end of the latching rocker to be able to be lockedover and securely engage the lifting knife for conjoint movement.

When it isdesired to either effect movement of the crank 2 or the crank3 or to possibly move both simultaneously, the lifting hook mounted atthe end of its upper arm is depressed to be shifted downwardly by animpulse directed in the direction of the arrow C or D, so that its outerend is removed from the catches 8a or 8b and its inner end is firmlylocked in engagement with the appurtenant lifting knife 60 or 6b.Preferably, the shifting of the rocker latch occurs during the restdwell of the dobby mechanism as a whole, that is, when the lifting knifeabuts against the stop on the upper amt of the crank and when the upperarm of the crank itself abuts against the fixed stops 9a or 9b. Thelocking of the latching rocker on to the lifting knife thereafterpermits the lifting knife 6a or 6b, which is positively driven tooscillate about the center of the axles 1a and 1b, to conjointly carrywith it and move in a coincident arcuate path the lifting cranks 2 or 3;turning the lifting crank 3 counter clockwise while turning the liftingcrank 2 clockwise. in the reverse motion created by the dobby drive thelifting knives 6a or 612 carry the levers 2 and 3 in the contrarydirection swining them outwardly from each other and placing them backto their initial position against the fixed stops 9a and 9b. When thisoccurs the springs 7a and 7b again act to lock the latches over thestationary catches 8a and 8b maintaining the lifting cranks 2 or 3 atrest, where they remain so so long as an impulse is not exerted ineither of the directions C or D.

Each of the lifting cranks is provided with a depending arm extending atan angle away from the arm on which the latches are mounted. The end ofthe depending arm of the lifting crank 2 is pivotally connected at apoint 10 to the end of a tie rod 11 which is pivotally connected at itsopposite end 12 to a balancing lever 13. The balancing lever 13 ispivotally connected at one end 14 to the end of the depending arm of thelifting crank 3 and its opposite end 15 at a pivotal connection with abar or shaft 16 secured by a means arrangement to the heald frame.

it will be seen that when the lifting crank 2 is rotated clockwise byits engagement with its associated lifting knife, the point 10 swingsfrom its initial position E through an are 01 into a lifting position Fwhile if the lifting crank 3 is swung counter-clockwise from its initialposition G through an angle a into its lifting position H and thebalancing lever 13 will move correspondingly and consequently actuatethe connection 16 with the heald frame.

Upon operation of the dobby to move either or both of the lifting cranksthe balancing lever might take one of three variations:

I. If the liftingcrank 2 is maintained at rest and the lifting crank 3is moved counter-clockwise then the end 14 of the lifting crank 3 willswing through an are 1,, from its initial position G into the position Hand back, and the balancing lever 13 will pivot about the point 12 atwhich it is connected to the tie rod 11, since this point 12 remains atits initial position because the tie rod 11 is tied at poing 10 to thelifting crank 2 which is held stationary in its rest position. Thuspoint 15 at the end of the lever 13 derives a positive swinging motionmoving in arc 1 from position] into position K and back.

2. if the lifting crank 3 is maintained at its rest position and thelifting crank 2 is made to. perform its swinging motion then the point10 at the end of the lifting crank 2 swings an arcuate distance I, fromposition E into position F and back. The tie rod 11 is thus caused topivot the lever 13 about the point 14 at the end of the depending arm ofthe lifting crank 3, moving the lower end 15 of the lever from itsposition J into the position K as in the first variation.

3. Should both the lifting cranks 2 and 3 be caused to sequentiallyswing then a double lift effect can be made to occur in that the end ofthe lever 13 can be made to remain for the required number of lifts inthe position K and consequently the heald frame can be made to remainstationary for a period of time in its upper position. This double lifteffect can be initiated when either one of the lifting cranks 2 and 3are swung clockwise or counter-clockwise in to their lifting positionand then sequentially placing the other lifting crank into its liftingposition. By alternating actuation on the latches of the rockers 5a and5b during the oscillating or reverse motion of the dobby, in sequence,then the end of the balancing lever 13 can be maintained in position K.In this manner the point 14 at the end of the depending arm of thelifting crank 3 moves from position H to the position G and the point 10at the end of the depending arm of the lifting crank 2 movesfrom theposition E into position F so that the pin 15 remains at the point Kindefinitely.

The length of the shift of the point 15 between the positions J and Kcanbe adjusted by varying the length of the tie rod 11 or its point ofconnection 12 on the lever 13. This can easily accomplished by providingthe tie rod 11 and the lever 13 with several-receiving holes at each endthrough which the pins 10 and 12 securing the tie rod to the crank 2 andlever 13 and can be easily inserted. The relationship of the dimensionsof the crank arms with respect to the tie rod and lever 13 are ofimportance with providing the proper swing unto the lever 13 and thusthe proper length of actuation of the member 16 so as to lift the healda predetermined distance. To understand this relationship the followingnotations have been used in the drawings.

. d: represents the overall length of the balancing lever 13, a:represents the length of the depending arm of the lifting crank 2,

b: represents the length of the depending arm of the lifting crank 3,

the angle alpha 6! represents the angular deviation of the separatearrns aand b of each of the swinging levers of each of the liftingcranks ,2 and 3.

1 represents the lifting length or swing arc of the point 10 at the endof the depending arm of the lifting crank 2, I equals the lifting lengthor swing arc of the point 14 at the end of the'depending arm of thelifting crank 3, and

I equals the length of the resulting lift or swing arc point 12 and theend 15 of the lever .13. As has been explained further, it may bedesirable to adjust or vary the position of the point 12 with regard tothe ends of the lever 13 so that the fulcrum point which it establisheswhen the lifting crank 2 is held in rest or dwell position can be variedand length of the arm between point 12 and point may consequently bevaried.

d: The optimum movement of the lever 13, when engaged in the firstvariation noted above, is accomplished when the point 15 is swung in anare having the relationship l =1 (c/d c) The optimum arrangement forproceeding under the second variation is accomplished when therelationship exists for the swing arc of point 15.

From the above relationships it follows that since 1 as in the firstcase, is equal to 1 in the second case that the actual relationship ofthe arms a and b can be expressed as follows:

Thus the preferred ratio stated earlier is'satisfied.

By either shortening the connecting rod 11, or by shifting the positionof point 10 on the depending am of the lifting crank 2 or the point 12on the lever 13, the distance between the lever 13 and the crank 2 isvaried and thelength of the arm C is varied and thus the swing of thelever 13 from position J to K can be varied. In this way the possibilityis established for changing the movement of the arm 13 to vary theamount of lift or the distance that the heald frame is caused to beraised and lowered. Y Y

It will be seen from the foregoing that the articulated connectioncreated by the lever 13 and the tie rod 11 create a lever system havingtwo fulcrum points. With the fulcrum at point 12, when the lifting crank2 is held stationary, the lever 13 acts as a first order lever. On theother hand with the lifting crank 3 held stationary or in the restposition and the point 14 constituting the fulcrum, the lever l3 acts asa second order lever. From ther or both the levers can be transmitteddirectly to the apparatus for raising or lowering the heald without anysubsequent multiplication. By selecting the proper dimensions the crankarms and levers as well as the connecting rod the exact can be obtained.

Various modifications and changes will suggest them selves to thoseskilled in this art. Accordingly, the present disclosure is intended tobe illustrative only and not limiting the scope of the invention in anymanner.

What is claimed is: 1 l. A double lift dobby, jacquard loom and the likehaving a first and a second double arm crank, each crank being rotatablyjournaled about an axis spaced from and parallel to each other, one armof each of said cranks being provided with means for selectivelyengaging one of a pair of driven lifting knives to be rotated therebyabout its axis, the other arm of each of said cranks beingarticulatingly interconnected with the means for raising and loweringthe heald frame, said interconnection comprising a lever connected atone end to the first of said cranks and at its other end to the meansfor raising and lowering the heald frame and a tie rod connected at oneend to the second of said cranks and at its other end to the leverbetween the ends thereof to provide an articulated linkage having a pairof spaced fulcrum points so that one of .said fulcrums-is employed onthe actuation of a selected one of said cranks and'wherein said meansfor raising. and lowering the heald frame is actuable on rotation of oneor both of said cranks. V

2. The dobby according to. claim 1 wherein the size of the other arm ofsaid second crank relative to the other arm of said first'crank is equalto the ratio of the this arrangement it will be obvious that thenumerousadvantages can be obtained by which the motion of eidistancebetween the connection of said tie rod to said lever and the connectionof said lever to said means for raising and lowering the heald frame tothe entire length between the connecting ends of said lever.

3. The dobby according to claim 1 wherein the tie rod is adjustablypositioned at each end to said second crank and said lever respectively.

1. A double lift dobby, jacquard loom and the like having a first and asecond double arm crank, each crank being rotatably journaled about anaxis spaced from and parallel to each other, one arm of each of saidcranks being provided with means for selectively engaging one of a pairof driven lifting knives to be rotated thereby about its axis, the otherarm of each of said cranks being articulatingly interconnected with themeans for raising and lowering the heald frame, said interconnectioncomprising a lever connected at one end to the first of said cranks andat its other end to the means for raising and lowering the heald frameand a tie rod connected at one end to the second of said cranks and atits other end to the lever between the ends thereof to provide anarticulated linkage having a pair of spaced fulcrum points so that oneof said fulcrums is employed on the actuation of a selected one of saidcranks and wherein said means for raising and lowering the heald frameis actuable on rotation of one or both of said cranks.
 2. The dobbyaccording to claim 1 wherein the size of the other arm of said secondcrank relative to the other arm of said first crank is equal to theratio of the distance between the connection of said tie rod to saidlever and the connection of said lever to said means for raising andlowering the heald frame to the entire length between the connectingends of said lever.
 3. The dobby according to claim 1 wherein the tierod is adjustably positioned at each end to said second crank and saidlever respectively.